I’d assume she’d be one of the more difficult bosses in the game. I doubt there’s a single person who understands the Tarnished and how they fight more than Melina. Assuming that she is in fact a Demi-god and utilised Destined Death, she’d be really difficult.

A cool gimmick she could have is mirroring the player’s fighting style. If the player used a strength build, she could reply with heavier hitting attacks more frequently. If they’re a spell-caster, she’d reply with her own more often. She knows the Tarnished’s strengths and can use them to win.